Digital signatures can be used to sign data and applications, such as software, so that the data and applications can be trusted. Some digital signatures are associated with a digital signing certificate issued by a certificate authority. To maintain the integrity of the digitally signed data, the private key associated with the signing certificate should be stored in a secure location that is isolated from a network. Other devices, such as USB flash drives, may also not be used for storing the private key due to various vulnerabilities. Because the private key is stored in an inconvenient location, it can become cumbersome to access and use the key to digitally sign data and applications.